Fair Value Measurements - Fair Value of Assets and Liabilities Measured on Recurring Basis (Detail) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	$ 200	$ 1,445
Derivative liabilities	1
Total liabilities	1
Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	43	1,335
Fixed-Income Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	37	38
Redeemable Preferred Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	47	44
Foreign Currency Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency derivatives	73	28
Quoted Prices in Active Markets (Level 1) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	43	1,335
Quoted Prices in Active Markets (Level 1) [Member] | Money Market Funds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Money market funds	43	1,335
Significant Other Observable Inputs (Level 2) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	110	66
Derivative liabilities	1
Total liabilities	1
Significant Other Observable Inputs (Level 2) [Member] | Fixed-Income Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	37	38
Significant Other Observable Inputs (Level 2) [Member] | Foreign Currency Derivatives [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Foreign currency derivatives	73	28
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total assets	47	44
Significant Unobservable Inputs (Level 3) [Member] | Redeemable Preferred Stock [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investments	$ 47	$ 44